use heap sort for ascending integer sort

Belonging to [master]:
  - #2050

Compiler/BackEnd/ResolveLoops.mo

@@ -494,10 +494,10 @@ algorithm
         //print("there are both varCrossNodes and eqNodes\n");
         //at least get paths of length 2 between eqCrossNodes
         for i in 1:arrayLength(mIn) loop
-          arrayUpdate(mIn, i, List.sort(mIn[i], intGt));
+          arrayUpdate(mIn, i, List.heapSortIntList(mIn[i]));
         end for;
         for i in 1:arrayLength(mTIn) loop
-          arrayUpdate(mTIn, i, List.sort(mTIn[i], intGt));
+          arrayUpdate(mTIn, i, List.heapSortIntList(mTIn[i]));
         end for;
         eqCrossSet := AvlSetInt.addList(AvlSetInt.EMPTY(), eqCrossLstIn);
         paths := getShortPathsBetweenEqCrossNodes(AvlSetInt.listKeysReverse(eqCrossSet), eqCrossSet, mIn, mTIn, {}, findExactlyOneLoop);

Compiler/BackEnd/SymbolicJacobian.mo

@@ -1531,7 +1531,7 @@ algorithm
   for i in 1:listLength(inSparsePattern) loop
     tmpTuple := arrayGet(outSparsePattern,i);
     (value, tmplist) := tmpTuple;
-    tmplist := List.sort(tmplist, intGt);
+    tmplist := List.heapSortIntList(tmplist);
     tmpTuple := (value, tmplist);
     MetaModelica.Dangerous.arrayUpdateNoBoundsChecking(outSparsePattern, i, tmpTuple);
   end for;

Compiler/Util/List.mo

@@ -96,6 +96,7 @@ encapsulated package List
 "
 
 protected
+import Array;
 import MetaModelica.Dangerous.{listReverseInPlace, arrayGetNoBoundsChecking, arrayUpdateNoBoundsChecking, arrayCreateNoInit};
 import MetaModelica.Dangerous;
 import DoubleEndedList;
@@ -736,6 +737,16 @@ algorithm
   end for;
 end stripN;
 
+public function heapSortIntList
+  input output list<Integer> lst;
+algorithm
+  lst := match lst
+      case {} then lst;
+      case {_} then lst;
+    else arrayList(Array.heapSort(listArray(lst)));
+    end match;
+end heapSortIntList;
+
 public function sort<T>
   "Sorts a list given an ordering function with the mergesort algorithm.
     Example: